Magneto-Structural Correlations in Coordination Polymers Based on Formate Ligand and Transition Metal Cations

We present five three-dimensional (3D) coordination polymers (CPs) based on the formate ligand, [NaM(HCOO)<inf>3</inf>(H<inf>2</inf>O)]<inf>n</inf> with M = Co2+ and Ni2+ and [KM(HCOO)<inf>3</inf>]<inf>n</inf> with M = Mn2+, Co2+, and Ni2+, introducing three new nuclear structures with the P2<inf>1</inf> space group for [NaCo(HCOO)<inf>3</inf>(H<inf>2</inf>O)]<inf>n</inf> and [NaNi(HCOO)<inf>3</inf>(H<inf>2</inf>O)]<inf>n</inf>, and P6<inf>3</inf>22 Sohncke SG with chiral nuclear structure for [KNi(HCOO)<inf>3</inf>]<inf>n</inf>, along two centric C2/c isomorphs [KMn(HCOO)<inf>3</inf>]<inf>n</inf> and [KCo(HCOO)<inf>3</inf>]<inf>n</inf>. Magnetic measurements indicate that antiferromagnetic interactions predominate in the five CPs, with averaged antiferromagnetic zJ/k<inf>B</inf> mean values from −1.18 to −94.9 K. Moreover, magnetic long-range order (LRO) at low temperatures is evidenced by the magnetic susceptibility and heat capacity measurements. Furthermore, single-crystal and powder neutron diffraction experiments were performed to elucidate the magnetic structure, confirming the antiferromagnetic ordering with possible spin canting, thus understanding these systems’ magnetic exchange pathway topology. © 2025 The Authors. Published by American Chemical Society.